A structure for supporting an object by a shaft has been employed in various devices. In this structure, the shaft itself is supported by a base, and there are various types of structures for supporting the shaft.
For example, in a shaft supporting structure of Patent Document 1, an end of the shaft is inserted in a bearing hole formed in a casing. This restricts movement of the shaft in the radial direction. The shaft includes a restriction pin penetrating the shaft in the radial direction. A bracket extends from the casing along the shaft. The bracket includes an elongated hole extending parallel to the radial direction of the shaft. An end of the restriction pin is inserted in the elongated hole of the bracket. Movement of the shaft in the axial direction is restricted by the engagement between the restriction pin and the elongated hole.
In a shaft supporting structure of Patent document 2, a coil spring is fitted on the shaft, thereby pressing and fixing the shaft onto a fixing section of a frame by an elastic force of the coil spring. Specifically, the frame includes the fixing section formed by cutting the frame in the shape of L when viewed in plan, and the shaft is arranged at the fixing section. The coil spring is fitted on the shaft. The shaft includes a groove extending in the circumferential direction of the shaft, and the coil spring is fitted in the groove. Two arms extending from the ends of the coil spring are engaged with engagement holes formed in the frame, respectively. The two arms engage with the engagement holes in the frame, while biasing the coil spring to be tightened in the circumferential direction of the coil spring. As a result, the coil spring presses the shaft onto the fixing section of the frame, thereby restricting the radial movement of the shaft. Since the coil spring is fitted in the groove extending in the circumferential direction of the shaft, movement of the coil spring in the axial direction relative to the shaft is restricted. The coil spring is engaged with the engagement holes of the frame as described above, and therefore, it is fixed to the frame. That is, the axial movement of the shaft is restricted by the engagement between the coil spring and the frame, and the engagement between the coil spring and the groove.
Patent Document
PATENT DOCUMENT 1: Japanese Utility Model Application No. H02-29307
PATENT DOCUMENT 2: Japanese Patent Publication No. H06-236635